Control valves are used to control the flow of a gas, a liquid, and/or any other substance through the pipes and/or vessels to which they are connected. A control valve is typically composed of one or more inlets, one or more outlets, and may include a sleeve-like cage in which a valve plug operates to control fluid flow through apertures that fluidly couple the inlet(s) to the outlet(s). The valve plug is typically part of a bonnet assembly that is mechanically coupled (e.g., bolted, clamped, threaded into, etc.) to the valve body. An example control valve assembly is disclosed in U.S. Pat. No. 6,701,958, which is hereby incorporated by reference.
Control valves may be adapted to suit particular applications. Four common control valve types are the globe valve, the angle valve, the tee valve, and the vessel mounted valve. These four control valve types perform similar control functions, but are adapted for use in particular control applications.
A globe valve typically includes an inlet port or opening and an outlet port or opening aligned along a common flow axis. A globe valve also typically includes a valve bonnet assembly that is mounted to a third opening, which may be aligned along an axis that is perpendicular or at some other angle to the flow axis of the inlet and outlet ports. U.S. Pat. No. 6,701,958 referred to above describes an example of a globe valve assembly. A globe valve is typically used in applications in which a substantially straight-through flow path is desirable (e.g., if a valve is to be mounted in-line along a span of pipe).
An angle valve typically includes a first valve body opening, which is typically used as an inlet, disposed at an angle to a second valve body opening, which is typically used as an outlet. An angle valve also includes a valve bonnet assembly mounted to a third valve body opening that is aligned with the axis of either the inlet port or the outlet port or that is at an angle with respect to either the inlet port or the outlet port. An angle valve is typically used in applications where it is necessary to protect the valve body from erosion or flashing damage.
A tee valve is a hybrid or combination of a globe valve configuration and an angle valve configuration. A tee valve typically includes three ports each of which can be configured as an inlet or an outlet. Two of the ports are typically arranged in a coaxial configuration, while the flow axis of the other port is disposed at an angle relative to the flow axis of the two coaxial ports. A tee valve typically also includes a valve bonnet assembly mounted to a fourth valve body opening. A tee valve can be configured to function as a globe valve by plugging the port having a flow axis at an angle to the flow axis of the two coaxial ports.
A vessel mounted or non-freeze valve is configured similarly to an angle valve. Similar to an angle valve, a vessel mounted valve typically includes an inlet port and an outlet port having a flow axis at an angle relative to the flow axis of the inlet port. A vessel mounted valve also typically includes a third opening configured to accept a valve bonnet assembly. Additionally, vessel mounted valves are configured to be mounted directly to a vessel (i.e., without requiring any serially interposing piping, fittings, etc.) and may include threads external to the valve body for engagement with the internal threads of an aperture (e.g., a fitting) of the vessel to which the valve is to be mounted. In contrast to other valve types, the valve seat within a non-freeze valve is located near to the port that is mechanically coupled to the vessel. In this manner, the valve seat is exposed to the warmer temperatures of the vessel to which the valve is attached, thereby minimizing or eliminating the possibility of the valve seat freezing.
Thus, each of the four above-described valve types is capable of being used in one application or two different applications (e.g., in the case of the tee valve, which can be used as a globe valve or an angle valve depending on where the port plug is installed). However, none of the above-described types of valves enables flexible configuration of a valve body or assembly for use in vessel mounted (e.g., non-freeze) applications as well as angle valve and globe valve applications. As a result, valve manufacturers must purchase tooling and provide manufacturing facilities for at least the four different valve types described above. In addition, valve installers, maintenance personnel, etc. may be required to purchase and maintain a supply of four different types of valves to service such valves installed in a process plant.